We present the design and preliminary characterization of a cryogenic SiGe low noise amplifier optimized for direct integration with an SIS mixer. The LNA was designed to provide 25 dB gain over an IF frequency range of 4–8 GHz. The noise temperature of the LNA was simulated to be less than 6 K over the band at a power consumption of 720 μW. The LNA was directly connected to the SIS mixer block and measurement results yielded a minimum noise temperature of approximately 40 K at an LO frequency… CONTINUE READING